Dear Antonio,
   
   You wrote:
> Well if the PSU is OK then that only leaves a dead CD and I don't think
> there is too much you can do about that.
   Well, I can't whine because I have the CDU-561 working. Plus there is
the RRD40, although I haven't tested it.
   As for RRD40, I have disassembled the box and looked inside. As I was
suspecting, there is an adapter board between the SCSI bus and the drive.
The drive is connected to the board with a 16-conductor cable, but it's
quite likely that only 15 are used. Interestingly, the adapter board is not
made by DEC (DEC boards are very easy to tell, so I couldn't possibly me
mistaken). The only thing that's DEC is the EPROM chip with firmware. The
board appears to be made by Philips, as there are many Philips components
on it. It is also very likely to be Philips because the funny interface is
the same as on RRD50, which is a Philips drive. I couldn't tell whether the
drive itself is Philips or not since I didn't disassemble it far enough. I
also saw another connector on the drive that looked similar to the one
connected to the adapter board (I couldn't tell for sure for the same
reason). It wasn't connected to anything. Maybe the drive is dual-ported,
maybe it's for some kind of daisy-chaining, or maybe it's for something
else altogether. Note that the interface being Philips rather than DEC
suggests that it was either documented and intended to be general-purpose,
or Philips has intended it for some IBM PC card and DEC has later made an
MSCP equivalent of it. As for the box itself, it also appears to be
Philips. In any case, it's clear that it has been designed specifically for
this drive. I doubt that DEC would make a special box for this drive, since
they already had the generic one they use for RZ5x disks and TK50Z. Plus if
the whole design is Philips, they probably were selling it directly too,
and they had to have some box.
   
   Sincerely,
   Michael Sokolov
   Phone: 440-449-0299
   ARPA Internet SMTP mail: sokolov@alpha.ces.cwru.edu